Question

In nature, Legionella pneumophila is an intracellular parasite of free-living amoeba. The bacterium multiplies within these protists. However, if humans come into contact with water containing these parasitised amoeba, they can inhale aerosols containing L. pneumophila. Once in the lungs, immune cells phagocytose the bacteria, but the bacteria can survive in the immune cells and multiply therein. This ultimately leads to the symptoms of legionellosis (Legionnaire's disease). Which of the following most accurately describes the role of the amoeba in this process? Group of answer choices

The amoeba is the vector transmitting the bacterium from animals to humans

The amoeba serves as the reservoir for the disease

The amoeba exerts genetic reassortment for the bacteria

The amoeba is the index case

The amoeba is a fomite for persistence of the bacteria in the environment

The amoeba acts as the vehicle for transmission

Answer 1

Ans. The amoeba serves as the reservoir for the disease.

Legionella pneumophila is an aquatic intracellular parasitic bacteria that parasitized the free living amoeba. This bacterium is responsible for causing the disease legionnaires in human. In natural condition, the free living amoeba serves as the host where the legionellae multiply intracellularly. There by the amoeba provide an intracellular environment that is required for the replication of the bacteria. The host and parasite interaction is mostly affected by the nutritional condition, temperature and other elements. Several other protozoan species also favors the growth of Legionella.